关键词: 腹板斜裂缝, 主拉应力, 温度梯度, 疲劳, 钢纤维砼

Abstract: Based on the cracking investigation，some inclined cracks in webs apprearing in the continuous prestressed concrete box girder bridge in service phase are analyzed.Main factors inducing cracks are considered.such as temperature gradient，vehicular load，principal tensile stress of concrete，fatigue under temperature load and vehicular load.Proper temperature gradient should be selected in design phase to avoid crack.Some anti-rust coatings Can be daubed on the surface of the steel strands to protect them from corrosion by cavity seepage.Webs of box girder from one quarter to three quarters of each span may be poured with steel fiber reinforced concrete to avoid fatigue effect.

Key words: inclined crack in webs, principal tensile stress, temperature gradient, fatigue, steel fiber reinfomed concrete